Field of the Invention
The present invention relates to mobile communication.
Related Art
3rd generation partnership project (3GPP) long term evolution (LTE) evolved from a universal mobile telecommunications system (UMTS) is introduced as the 3GPP release 8. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in a downlink, and uses single carrier-frequency division multiple access (SC-FDMA) in an uplink. The 3GPP LTE employs multiple input multiple output (MIMO) having up to four antennas. In recent years, there is an ongoing discussion on 3GPP LTE-advanced (LTE-A) evolved from the 3GPP LTE.
As disclosed in 3GPP TS 36.211 V10.4.0 (2011-12) “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 10)”, a physical channel of LTE may be classified into a downlink channel, i.e., a PDSCH (Physical Downlink Shared Channel) and a PDCCH (Physical Downlink Control Channel), and an uplink channel, i.e., a PUSCH (Physical Uplink Shared Channel) and a PUCCH (Physical Uplink Control Channel).
Meanwhile, in a next-generation mobile communication system, it is expected that a small cell having a small cell coverage radius is added within a coverage of a macro cell.
In addition, a next-generation mobile communication system may be improved to use a high order modulation scheme, e.g., 256 quadrature amplitude modulation (QAM), in comparison with a small cell.
In order for a terminal to perform transmission by using the 256QAM modulation scheme, an error vector magnitude (EVM) must be significantly low. In this case, a dynamic range of a radio frequency (RF) element of the terminal must be increased to decrease the EVM, which causes an increase in power consumption and an increase in a battery consumption amount.